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10/20/2017 1:01:18 AM
9/22/2017 12:11:25 AM
Posted: 8/2/2005 6:34:33 PM EDT
OK electrical types:

I have an APC Back-UPS whose batteries have gone tits up. After I'm done chopping my way into it with a freaking fire axe, I know I can change the batteries easily enough (the old ones bulged & split). But I was wondering if I could just hook it up to a deep cycle battery and get more runtime.

Would the difference in electrical characteristics between a deep cycle and a pair of gel cells be enough to screw up the charging circuits in the UPS?
Link Posted: 8/2/2005 6:53:58 PM EDT
Well, the internal resistance of the deep-cycle battery would be lower, so potentially it could draw enough current to cause damage.

However, I suspect that the charging circuit will automatically limit the max current to a safe value.

I would go for it ...
Link Posted: 8/2/2005 7:00:36 PM EDT
I just ordered new batteries from APC.
Link Posted: 8/2/2005 7:06:11 PM EDT
It depends on the charging capacity of the original battery. Any APC 1000 or higher should be able to handle a deep cycle battery - AS LONG AS YOU USE THE PROPER SIZE CABLING!! Check with your local car audio shop for cabling and connectors. The easiest way to increase capacity is to buy a model that has the expansion port. The smaller varieties - the powerstrip looking ones, etc, won't really handle the capacity.. it will work until your first discharge cycle, and you will fry your circuts on the recharge. The Duty cycle on the smaller units won't handle the extended recharging.
Link Posted: 8/2/2005 7:09:53 PM EDT
Oops. I meant to mention it's an older Back-UPS 1250. Unfortunately, this one was built before they redesigned them so the batteries were easy to change. It's a mutha getting inside.
Link Posted: 8/2/2005 9:20:47 PM EDT

Originally Posted By BlammO:
But I was wondering if I could just hook it up to a deep cycle battery and get more runtime.



You can indeed, and the difference in runtime is...well, impressive.

The average UPS gell-cells are rated for 7 to 15 amp-hours, whereas the average Group 27 deep-cycle battery is rated for around 110 amp-hours. This translates into roughly 7 to 16 times longer run-time, for any given load.

However, there are several disadvantages:

1. Most deep-cycle batteries aren't sealed, which means that you'll have to add water every few months.

2. Non-sealed batteries give off explosive hydrogen gas, which makes good ventilation essential whenever they are located indoors.

3. Non-sealed batteries are messy - the connections tend to corrode, and spilled electrolyte can ruin your floors, your clothing or your skin.
Link Posted: 8/2/2005 9:30:11 PM EDT
[Last Edit: 8/2/2005 9:30:42 PM EDT by simplemitch]
Link Posted: 8/2/2005 10:32:26 PM EDT
Link Posted: 8/3/2005 8:56:28 AM EDT
Great info. I was looking at the Optima Yellow batteries online last night. I think I'll go that route. I suspect finding them locally might be a challenge, though.
Link Posted: 8/3/2005 9:27:01 AM EDT
Find a West Marine store, buy your chocie of Gel or AGM batteries.

Or do a web search for "Lifeline AGM" and find a dealer near you.

How about a 250AH 8D size?
Link Posted: 8/3/2005 10:02:53 AM EDT
Doh! There's a West Marine by the house! I come from a landlocked galaxy -- marine shops don't normally come to mind. Thanks!
Link Posted: 8/3/2005 11:29:17 AM EDT
Or, go to sears, auto department, look for a wheelchair battery. They're AGM. They've got a great warranty. they're decent price, etc. etc.

don't pay for an optima for this application - you want a true deep cycle, and sealed, therefore you don't want an Optima hybridized spiral cell battery. You'd be paying for features and attributes that you don't need, and getting less usability for your application than a true AGM will provide.

The sears wheelchair AGMs are about $70 if I remember correctly.
Link Posted: 8/3/2005 11:39:12 AM EDT
As somebody who replaces alot of UPS batteries let me give you one big piece of money saving advise...

Do not buy your batteries from APC.

They are overly expensive. Instead just call Interstate Batteries and tell them what you need. They will cost you about a quarter of the OEM ones and run just as well.
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